This invention relates in general to fasteners for securing two components together. More specifically, this invention relates to an improved structure for a threaded fastener having opposite hand threads provided thereon for securing two components together, such as a companion flange and a flange yoke that is used in a vehicular drive train system.
Drive train systems are widely used for generating power from a source and for transferring such power from the source to a driven mechanism. For example, in most land vehicles in use today, an engine/transmission assembly generates rotational power, and such rotational power is transferred from an output shaft of the engine/transmission assembly through a driveshaft assembly to an input shaft of an axle assembly so as to rotatably drive the wheels of the vehicle. To accomplish this, a typical driveshaft assembly includes a hollow cylindrical driveshaft tube having a pair of end fittings, such as a pair of tube yokes, secured to the front and rear ends thereof. The front end fitting forms a portion of a front universal joint that connects the output shaft of the engine/transmission assembly to the front end of the driveshaft tube. Similarly, the rear end fitting forms a portion of a rear universal joint that connects the rear end of the driveshaft tube to the input shaft of the axle assembly. The front and rear universal joints provide a rotational driving connection from the output shaft of the engine/transmission assembly through the driveshaft tube to the input shaft of the axle assembly, while accommodating a limited amount of angular misalignment between the rotational axes of these three shafts.
A companion flange and flange yoke assembly is often used to connect the output shaft of the engine/transmission assembly to the front universal joint or to connect the rear universal joint to the input shaft of the axle assembly. A typical companion flange and flange yoke assembly includes a companion flange and a flange yoke that are secured together for concurrent rotational movement. The companion flange includes a hollow cylindrical, internally splined sleeve portion that engages the shaft for rotation therewith, while the flange yoke includes a yoke portion that forms a portion of the associated universal joint. The companion flange and the flange yoke are typically secured together using fasteners that extend through aligned apertures formed through mating flange portions of the companion flange and the flange yoke. Respective nuts are threaded onto the ends of the threaded fasteners to retain the companion flange and the flange yoke together during use.
In order to insure that the companion flange and the flange yoke are reliably secured together, it is important that the nuts are tightly rotated onto the ends of the threaded fasteners. Because of the relatively large amount of torque that is usually needed to be applied to such nuts during installation, it is often necessary to positively prevent the threaded fasteners from rotating while the nuts are being tightened thereon. The simplest method of accomplishing this would be to use a wrench or other tool to engage conventional heads on the threaded fasteners to prevent them from rotating when the nuts are tightened thereon. However, such a method has been found to be somewhat awkward and difficult because of space constraints, and further is relatively time consuming in the context of the high volume production of vehicular drive train systems. A more recent method has been to provide a knurled portion on each of the threaded fasteners that frictionally engages either the companion flange or the flange yoke in an attempt to prevent the threaded fasteners from rotating when the nuts are tightened thereon. Although much simpler and quicker than using a wrench or similar tool, these knurled structures have, at least in some instances, been found to provide an insufficient amount of resistance to prevent the threaded fasteners from rotating when the nuts are tightened thereon. Thus, it would be desirable to provide an improved structure for a threaded fastener for use in a companion flange and flange yoke yoke assembly that more effectively prevents the threaded fasteners from rotating when the nuts are tightened thereon.